基于焦点分段的流媒体代理缓存策略

Popular segment-based proxy caching for streaming media over internet

在已有前缀缓存和分段缓存算法研究的基础上,提出了基于焦点分段的流媒体代理缓存策略。该策略考虑到不同流媒体对象在流行性方面的差异和同一对象不同段落上访问频率的差异,以段落的流行度作为空间调度的依据,融合了部分前缀缓存的方法,避免了自适应滞后分段缓存算法在延时启动率方面的不足。实验结果表明:基于焦点分段的缓存策略在字节命中率、延时启动率等方面都取得了较好的效果,缓存空间的利用率和节省网络带宽的能力都有所提高。

A popular segment-based proxy caching scheme for streaming media was proposed. This scheme was based on the existing technologies, such as the prefix and segment-based caching strategies. In this scheme the fact that most accesses are targeted toward a few popular objects or partials of an object is taken into account. The popular segments are cached on the client and the size can be dynamically changed according to the client access behaviors in real time. The admission and eviction of segments are carried out by an accurate utility function, which is better than the adaptive and lazy segment caching strategies in improving the client perceived startup latency. Simulation results indicate that, comparing with existing strategies, the proposed scheme performs better in byte hit ratio, client startup delay, network traffic and cache space.